DESCRIPTION OF A SALMON EGG. 7 



men find particular kinds of fish always on particular ground ? 

 How is it that eels migrate in immense bodies ? My opinion 

 is, that particular kinds of fish do hold always together, or, 

 at all events, gather at particular seasons into greater or 

 lesser bodies. Life among the inhabitants of the sea is, doubt- 

 less, quite as diversified as life on land, where we observe that 

 many kinds of animals colonise — ants, bees, etc. Are, therefore, 

 the old stories about each kind of fish having a king so abso- 

 lutely incredible after all ? That there are schools of fish is cer- 

 tain ; how the great bodies may be divided or governed, none can 

 teU. 



It is noteworthy that fish-eggs afibrd us an admirable oppor- 

 tunity of studying a peculiarly interesting stage of animal life — 

 namely, the embryo stage — ^which, naturally enough, is obscure 

 in all animals. Having observed the eggs of salmon in all 

 stages of progress, from the period of their first contact with the 

 milt till the bursting of the egg and the coming forth of the 

 tiny fish, I venture briefly to describe what I have seen, because 

 salmon eggs are of a convenient size for continued examination. 

 The roe of this fine fish is, I daresay, pretty familiar to most 

 of my readers. The microscope reveals the eggs of salmon as 

 being more oval than round, although they appear quite round 

 to the naked eye. A yolk seems to float in the dim mass, 

 and the skin or shell appears fuU of minute holes, while 

 there is an appearance of a kind of funnel opening from the 

 outside and apparently closed at the inner end. The milt is 

 found to swarm with a species of very small creatures with big 

 heads and long tails, apparently of very low organisation. On 

 the contact of this fluid with the egg, into which it enters by 

 the canal, an immediate change takes place — the ovum becomes 

 illuminated by some curious power, and the egg appears a great 

 deal brighter and clearer than before. It is surely wonderful 

 that, by the mere touching of the egg with this wonder-working 

 sperm, so great a change should take place — a change indicating 

 that the grand process of reproduction characteristic of all living 

 nature has begun, and will go on with increasing strength to 

 maturity. 



Salmon-spawn is so accessible, comparatively speaking, as 

 to render it easy to trace the development from the egg of the 

 complete animal. As may be supposed, however, the transmu- 

 tation of a salmon egg into a fish is a tedious process, taking 

 above a hundred days. The eggs of the female, under the 



